Somdev was leading 6-4, 4-2 when the German decided to concede the match.

Sania Mirza, who made a first round exit in women's singles on Tuesday, is doubtful for the doubles owing to a painful left knee injury. She will decide on her participation after an ultrasound scan.

Somdev, ranked 68th, next plays 18th seed and World No.17 Mikhail Youzhny of Russia who was stretched to five sets by Juan Monaco of Argentina before winning 4-6, 6-2, 6-2, 4-6, 6-4.

Younzy beat Somdev in straight sets in their only meeting in the Davis Cup World Group tie last year at Moscow.

This is Somdev's maiden singles appearance here. The only time the 26-year-old got past the first round of a Grand Slam was when he reached the US Open second round in 2009.

Sania, who was already carrying a niggling left knee problem, "tweaked" it early in the first set of her 6-7(4), 6-2, 3-6 loss to Virginie Razzano.

"I've had the same injury since just before the French Open. I've been playing a lot on it," Sania said.

"I tweaked it at 3-0 in first set. It is very, very painful. I can still serve but I can't move and change direction. "I have to see the doctor and get an ultrasound scan."

Sania along with Russia's Elena Vesnina is seeded fourth in the women's doubles and the two are rated serious trophy contenders after their final appearance in the French Open earlier this month. The Indian was also to play in the mixed doubles.